D'où l'importance d'être bien précis dans les demandes. Essayez ceci:
Private Sub Worksheet_Change(ByVal Target As Range)
Dim f1 As Worksheet, f2 As Worksheet
Dim DerLig_f1 As Long, i As Long
Dim x As Range
Dim Produit As String
On Error GoTo Sortie
Application.EnableEvents = False
If Target.Column = 3 Then
Set f1 = Sheets("Feuil1")
Set f2 = Sheets("Liste")
Produit = Left(Target, InStr(1, Target, " ") - 1)
With f2.Cells
Set x = .Find(Produit, lookat:=xlPart)
If Not x Is Nothing Then f1.Cells(Target.Row, "B") = f2.Cells(x.Row, "C")
End With
Set f1 = Nothing
Set f2 = Nothing
End If
Sortie:
Application.EnableEvents = True
End Sub